CN216929581U - Single-fire electricity-taking protection circuit and equipment - Google Patents

Single-fire electricity-taking protection circuit and equipment Download PDF

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Publication number
CN216929581U
CN216929581U CN202123269974.4U CN202123269974U CN216929581U CN 216929581 U CN216929581 U CN 216929581U CN 202123269974 U CN202123269974 U CN 202123269974U CN 216929581 U CN216929581 U CN 216929581U
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resistor
protection circuit
specified
live wire
current
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杨亚北
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Wuhan Linptech Co Ltd
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Wuhan Linptech Co Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection

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Abstract

The utility model provides a single live wire power-taking protection circuit and equipment, wherein the single live wire power-taking protection circuit comprises: the resistor is directly or indirectly connected in series in a loop of the single live wire electric protection circuit; a circuit abnormality detector connected in series to the resistor and arranged to detect a first state parameter of the resistor, entering a high impedance state upon detection of the first state parameter being in a first specified interval starting at a first specified threshold. The protection circuit can protect the product safety under the abnormal state of the power-taking circuit, and can not generate the phenomena of heating, firing and the like.

Description

Single-fire electricity-taking protection circuit and equipment
Technical Field
The utility model relates to the field of switches, in particular to a single-fire electricity taking protection circuit and equipment.
Background
Along with the development of intelligent house, more and more consumers wish to purchase intelligent house class product, wherein intelligent switch is indispensable partly to the control of light etc, and general light control line, be a live wire, and there is not the zero line, therefore the demand of intelligent switch can't be satisfied to conventional power supply mode, need design the circuit of only getting the electricity with a live wire, under the condition of only using a live wire, the lamp is when the off-state, need get the electricity work with the help of the leakage current of lamp, just so can lead to the lamp to flash occasionally under the state of closing because of the leakage current of lamp.
In the prior art, in order to suppress the flicker problem, a resistor may be connected in series in the power-taking circuit, but in an actual use situation, the resistor often generates heat due to an abnormal state of the power-taking circuit, and thus damages the circuit and the equipment.
SUMMERY OF THE UTILITY MODEL
The utility model provides a protection circuit for single live wire power supply, which aims to solve the technical problems that a resistor in an existing single live wire power supply loop generates heat and damages a circuit board and an equipment shell due to the fact that abnormal current flows through the resistor for a long time.
According to a first aspect of the present invention, there is provided a single live wire protection circuit, comprising:
the resistor is electrically connected in the single live wire power taking protection circuit;
a circuit abnormality detector connected in series to the resistor and adapted to detect a first state parameter of the resistor, and enter a high impedance state upon detecting that the first state parameter is in a first specified interval starting at a first specified threshold.
Further, the circuit abnormality detector is further configured to, when detecting that the first state parameter is in a non-first specified range, release the high impedance state to recover normal operation of the single live wire protection circuit.
Further, a clamping device for limiting a voltage across the resistor is not connected in parallel across the resistor.
Further, the circuit abnormality detector includes a positive temperature coefficient recoverable fuse; the positive temperature coefficient restorable fuse is connected in series with the resistor and is directly or indirectly electrically connected with a rectifying unit; and the rectifying unit is used for rectifying and outputting the input current of the single live wire power-taking protection circuit.
Further, the PTC recoverable fuse is electrically connected to the rear end of the rectifying unit after being connected in series with the resistor; namely, one end of the positive temperature coefficient recoverable fuse is used as an input end to be directly or indirectly electrically connected to the anode or the cathode of the rectifying unit, and the other end of the positive temperature coefficient recoverable fuse is used as an output end to be electrically connected to the resistor and used for detecting the current of the resistor.
Further, the positive temperature coefficient recoverable fuse is electrically connected to the front end of the rectifying unit after being connected in series with the resistor, namely, between the live wire end of the single live wire power-taking protection circuit and the rectifying unit, or between the zero line end of the single live wire power-taking protection circuit and the rectifying unit, and is used for detecting the current of the resistor.
Further, the first state parameter comprises a current of the resistor, the first specified threshold comprises a specified current threshold, the first specified interval comprises a specified current interval; when the first state parameter is detected to be in a first specified interval taking a first specified threshold value as a starting point, entering a high impedance state; the method specifically comprises the following steps:
and when the current of the resistor is detected to be in a specified current interval with a specified current threshold as a starting point, entering a high impedance state to limit the current of the resistor within the specified current threshold range.
Further, the first state parameter comprises a current of the resistor, the first specified threshold comprises a specified current threshold, and the non-first specified interval comprises a non-specified current interval; when the first state parameter is detected to be in a non-first specified range, the high impedance state is released; the method specifically comprises the following steps:
and when the current of the resistor is detected to be in a non-specified current interval, the high impedance state is released.
Furthermore, the single live wire power-taking protection circuit is provided with a plurality of paths of loads in parallel, and correspondingly, each path of load is connected to a rectifying unit; the positive temperature coefficient recoverable fuse is connected to a loop shared by all the rectifying units.
Further, the PTC recoverable fuse has an operating current in the range of 5mA to 100 mA.
Further, the PTC recoverable fuse is characterized in that the operating current of the PTC recoverable fuse is set to 20 mA.
Further, the PTC recoverable fuse is characterized in that the current of the resistor is less than or equal to 10mA in a balanced state.
Further, the circuit abnormality detector includes a temperature fuse; the temperature fuse device is connected in series with the resistor and is directly or indirectly electrically connected with a rectifying unit; and the rectifying unit is used for rectifying and outputting the input current of the single live wire power-taking protection circuit.
Further, the temperature fuse device is electrically connected to the rear end of the rectifying unit after being connected in series with the resistor; namely, the input end of the temperature safety device is directly or indirectly electrically connected to the anode or the cathode of the rectifying unit, and the output end of the temperature safety device is electrically connected to the resistor for detecting the temperature of the resistor.
Further, the temperature safety device is electrically connected to the front end of the rectifying unit after being connected in series with the resistor, namely, a live wire end of the single live wire power-taking protection circuit is connected between the rectifying unit and the live wire end of the single live wire power-taking protection circuit, or a zero wire end of the single live wire power-taking protection circuit is connected between the rectifying unit and the live wire end of the single live wire power-taking protection circuit, and the temperature safety device is used for detecting the temperature of the resistor.
Further, the first state parameter comprises a temperature, the first specified threshold comprises a specified temperature threshold, and the first specified interval comprises a specified temperature interval; when the first state parameter is detected to be in a first specified interval taking a first specified threshold value as a starting point, entering a high impedance state; the method specifically comprises the following steps:
is blown to assume a high impedance state of infinite resistance when the temperature of the resistor is detected to be in a specified temperature interval starting at a specified temperature threshold.
Further, the operating temperature of the temperature safety device is set to be 120 ℃ to 200 ℃.
Further, the temperature fuse and the resistor are both disposed on a PCB, and a distance between the temperature fuse and the resistor on the PCB is less than a threshold distance; and a heat conducting material is coated between the temperature fuse element and the resistor.
Further, the temperature safety device and the resistor are packaged into a whole, so that the temperature safety device can accurately detect the temperature of the resistor.
According to a second aspect of the present invention, there is provided a single live wire protection circuit, comprising:
a resistor; and
a clamping device connected in parallel across the resistor and configured to detect a second state parameter of the resistor, and enter a clamping state to protect the resistor when the second state parameter is detected to be within a second specified interval starting at a second specified threshold.
Further, the clamping device is further configured to release the clamped state upon detection that the second state parameter is in a non-second specified range.
Further, either end of the resistor is not connected in series with a circuit abnormality detector for limiting the resistor current.
Further, the clamping device comprises a first clamping diode; the first clamping diode and the resistor are connected in parallel and then electrically connected to the rear end of a rectifying unit, namely the first clamping diode and the resistor are connected in parallel and then electrically connected to the anode or the cathode of the rectifying unit and used for detecting the voltage at two ends of the resistor; and the rectifying unit is used for rectifying and outputting the current input by the power input stage of the single live wire power-taking protection circuit.
Further, the clamping device comprises a first clamping diode; the first clamping diode is electrically connected to the front end of a rectifying unit after being connected in parallel with the resistor, namely, the first clamping diode is arranged between the live wire end of the single live wire power-taking protection circuit and the rectifying unit or between the zero line end of the single live wire power-taking protection circuit and the rectifying unit and used for detecting the voltage at the two ends of the resistor; and the rectifying unit is used for rectifying and outputting the current input by the power input stage of the single live wire power-taking protection circuit.
Further, the clamping device comprises a second clamping diode and a third clamping diode; the ends of the second clamping diode and the third clamping diode with the same polarity are electrically connected, and the two ends which are not connected correspondingly are connected in parallel with the two ends of the resistor; the second clamping diode and the third clamping diode are electrically connected to the rear end of a rectifying unit after being connected in parallel with the resistor, namely the second clamping diode and the third clamping diode are electrically connected to the anode or the cathode of the rectifying unit after being connected in parallel with the resistor and are used for detecting the voltage at two ends of the resistor; and the rectifying unit is used for rectifying and outputting the current input by the power input stage of the single live wire power-taking protection circuit.
Further, the clamping device comprises a second clamping diode and a third clamping diode; the second clamping diode and the third clamping diode are electrically connected to the front end of a rectifying unit after being connected in parallel with the resistor, namely between the live wire end of the single live wire power-taking protection circuit and the rectifying unit, or between the live wire end of the single live wire power-taking protection circuit and the rectifying unit, and are used for detecting the voltage at two ends of the resistor; and the rectifying unit is used for rectifying and outputting the current input by the power input stage of the single live wire power-taking protection circuit.
Further, the second state parameter comprises a voltage, the second specified threshold comprises a specified voltage threshold, and the second specified interval comprises a specified voltage interval; when the second state parameter is detected to be in a second specified interval taking a second specified threshold value as a starting point, entering a clamping state; the method specifically comprises the following steps:
and when the voltage across the resistor is detected to be in a specified voltage interval with a specified voltage threshold as a starting point, entering a clamping state to limit the voltage across the resistor within the specified voltage threshold range.
Further, the second state parameter comprises a voltage, the second specified threshold comprises a specified voltage threshold, and the non-second specified interval comprises a non-specified voltage interval; when the second state parameter is detected to be in a non-second specified range, the clamping state is released; the method specifically comprises the following steps:
and when the voltage at the two ends of the resistor is detected to be in a non-specified voltage interval, the clamping state is released.
According to a third aspect of the present invention, there is provided an electronic device comprising the single live line protection circuit.
The utility model has the beneficial effects that: the technical scheme provided by the utility model detects the abnormal condition of the circuit by arranging a circuit abnormality detector connected in series with a resistor or a clamping device connected in parallel with the resistor; when a circuit abnormity detector connected in series with a resistor is used, the current or the temperature of the resistor is detected, and when the current or the temperature of the resistor is abnormal, the circuit abnormity detector enters a high-impedance state to rapidly pull down the current of a loop, so that the aim of protecting the resistor and the whole circuit is fulfilled; when a clamping device connected in parallel is used, the voltage across the resistor is detected, and when the voltage of the resistor is abnormal, the clamping device enters a clamping state to limit the voltage across the resistor within a threshold range so as to indirectly prevent the increase of loop current and protect the resistor and the circuit. In addition, according to the technical scheme provided by the application, only one of the circuit abnormality detector and the clamping device needs to be selected as a protection measure for taking electricity by single fire, and a better protection effect can be achieved under the condition of lower cost.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1-1 is a circuit diagram of a fire-taking protection circuit in embodiment 1 of the present invention;
FIG. 1-2 is a schematic circuit diagram of the clamp device of FIG. 1-1 after the clamp device has been added;
FIGS. 1-3 are schematic diagrams of RT curves for the PTC recoverable fuse of FIGS. 1-1;
fig. 2-1 is a circuit diagram of a fire power protection circuit in embodiment 2 of the present invention;
FIG. 2-2 is a schematic circuit diagram of the circuit of FIG. 2-1 after the addition of a clamping device;
fig. 3 is a circuit diagram of a fire power protection circuit in embodiment 3 of the present invention;
fig. 4-1 is a circuit diagram of a fire-taking protection circuit in embodiment 4 of the present invention;
FIG. 4-2 is a schematic circuit diagram of FIG. 4-1 with the addition of a clamping device;
fig. 5-1 is a circuit diagram of a fire-taking protection circuit in embodiment 5 of the present invention;
FIG. 5-2 is a schematic circuit diagram of the circuit of FIG. 5-1 after the addition of a clamping device;
fig. 6 is a circuit diagram of a fire power protection circuit in embodiment 6 of the present invention;
fig. 7 is a circuit diagram of a single-fire power-taking protection circuit in embodiment 7 of the present invention;
fig. 8 is a circuit diagram of a fire power protection circuit in embodiment 8 of the present invention;
fig. 9 is a circuit diagram of a fire power protection circuit in embodiment 9 of the present invention.
Reference numerals are as follows:
1-AC-DC switching power supply;
2-communication and control circuitry;
3-circuit anomaly detector, R2-positive temperature coefficient recoverable fuse;
an L-live wire connecting end and an N-zero line connecting end;
r1, R4, R3-resistor;
s1, S2, S3-switching device;
MB1, MB 2-rectifying unit;
l1, L2, L3 — external load;
4-a clamp device;
d1, D2-clamp diodes;
d3-first clamping diode, D4-second clamping diode, D5-third clamping diode.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The terms "first," "second," "third," "fourth," and the like in the description and in the claims, as well as in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the utility model described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
In the description of the present invention, "multiple" means a circuit in which a plurality of loads are located, such as two, three, four, etc., unless otherwise specifically limited.
In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected" and the like are to be construed broadly, e.g., as meaning permanently attached, releasably attached, or integral to one another; can be mechanically connected, electrically connected or can communicate with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
It should be noted that, in all the following descriptions, "on" refers to a conducting state, or an on state, through which a current flows; "off" refers to a non-conductive state, or open state, in which no current flows.
With the development of smart homes and IOT technologies, smart switches are becoming more and more popular. The intelligent switch needs a live wire and a zero wire to supply power to a communication and control circuit of the intelligent switch (for example, the communication circuit and the processor are powered to work normally). However, there are some older houses, and the line from the zero line to the switch is not configured during decoration, that is, only a single live line exists, and the existing intelligent switch of the zero live line cannot be used. Therefore, an intelligent switch with a single live wire power-taking mode is generated, and a single live wire power-taking circuit is used in the intelligent switch; the principle is as follows: the single live wire electricity-taking circuit of the intelligent switch is connected in series in a power supply circuit of a load (such as a lamp), namely, one wiring terminal of the single live wire electricity-taking circuit is connected to a live wire connecting end, the other end of the single live wire electricity-taking circuit is connected to a zero line connecting end through the load, and then a part of electric quantity is taken in a power supply loop of the load to supply power for the communication and control circuit of the intelligent switch, so that the intelligent switch can normally work. The intelligent switch is connected in series in a working loop of a load, electric energy needs to be obtained from the loop, if the intelligent switch is continuously in a standby state, a lamp loop needs to continuously provide certain working current, and if the working current is too large, a lamp can emit slight light or twinkle, so that the use experience of a user is influenced; therefore, in the single live wire power supply circuit, in order to inhibit the flicker problem of the load in the single live wire power supply circuit, a resistor can be connected in series in the power supply circuit to limit the current of the working loop; however, the resistor may pass a certain current for a long time due to an abnormal condition of the circuit, the current is directly related to the resistance of the resistor as a protection resistor and a load, and if the resistor is in an abnormal current state for a long time (for example, the current flowing through the resistor is greater than a certain threshold), the abnormal current may flow for a long time to generate heat, and the circuit board and the device housing may be damaged. In an example, the failure fault is a short-circuit-like circuit fault, for example, the input stage of the AC-DC switching power supply 1 shown in fig. 1-1 is short-circuited, which is equivalent to that the whole circuit is short-circuited, and in this failure fault, the current flowing through the resistor R1 is larger than normal current, which causes R1 to generate heat, and the circuit board and the device housing are burnt out due to long-term heat generation. Therefore, in order to solve the technical problem, the embodiment provides a single live wire protection circuit, which is used for protecting the resistor when the circuit for single live wire power taking is abnormal, so as to protect the whole single live wire circuit and the corresponding electrical equipment.
The technical solution of the present invention will be described in detail below with specific examples. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments. It should be noted that, in the following drawings of all embodiments, the single hot wire power taking protection circuit is mainly shown, and since the single hot wire power taking technology is relatively mature and related circuits are disclosed by many documents, the whole single hot wire power taking circuit and the power taking principle will not be discussed too much in the drawings of this specification.
Referring to fig. 1-1 to 1-3, the single hot line protection circuit of embodiment 1 is specifically illustrated based on fig. 1-1 to 1-3; fig. 1-1 is a simple schematic diagram of a single live line protection circuit provided in embodiment 1 of the present invention; as shown in fig. 1-1, the single hot line protection circuit provided in this embodiment at least includes:
a resistor R1 electrically connected in the single live power protection circuit; and the circuit abnormity detector 3 is connected in series with the resistor R1 and is set to be suitable for detecting the first state parameter of the resistor R1, and when the first state parameter is detected to be in a first specified interval taking a first specified threshold value as a starting point, the high-impedance state is entered to protect the resistor R1, so that the aim of protecting the whole circuit is fulfilled. When the first state parameter is in the first designated interval starting from the first designated threshold, that is, it is determined that the circuit is abnormal, the current flowing through the resistor R1 may be rapidly increased to cause the resistor R1 to generate heat, thereby damaging the whole circuit; therefore, the circuit abnormality detector 3 enters a high impedance state to limit a continuous increase in the current in the resistor R1 to protect the resistor R1. Illustratively, the resistor R1 is implemented as a flash suppression resistor, and the resistor R1 is used for limiting the current flowing through the external load L1, so that the existence of the resistor R1 makes the current flowing through the external load L1 not too large, and the problem of flash of the external load L1 in the off state can be suppressed; the resistor R1 is set to have a resistance value in the range of 300 Ω to 5k Ω, preferably 500 Ω, 1k Ω, 3.2k Ω, etc. For example, when the resistor R1 needs to have a surge suppression effect, the resistor R1 may also be implemented as a resistor with surge suppression capability, or a resistor unit with surge suppression capability formed by connecting a plurality of resistors in series; it should be noted that, the series connection of a plurality of resistors can increase the power margin and surge suppression capability of the resistor, for example, a resistor of 3.2k Ω, and a resistor of 4 800 Ω can be used in series connection. Of course, the above two embodiments are only examples and are not intended to limit the present invention.
As shown in fig. 1-1, the resistor R1 and the circuit abnormality detector 3 are electrically connected in series between an AC-DC switching power supply 1 and a rectifying unit MB 1; the rectifying unit MB1 is used for rectifying the input current of the single live wire protection circuit and inputting the rectified input current into the AC-DC switching power supply 1 at the rear end through the resistor R1, and the AC-DC switching power supply 1 converts the input electric energy and outputs the converted electric energy to the communication and control circuit 2; the communication and control circuit 2 is used for communicating with the outside and receiving a control instruction, and controls the on-off state of a switch device S1 connected to the single live wire power supply protection circuit according to the control instruction, so as to control the working state of an external load L1 associated with the switch device S1. Wherein, the control end of the switching device S1 is electrically connected to the communication and control circuit 2 (not shown), and is configured to be switched on and off by the communication and control circuit 2; when the switching device S1 is turned off, the external load L1 is turned off, and the power supply loop of the external load L1 is cut off, so that the external load L1 is not lighted at this time, and a power supply loop is formed at this time through the hot terminal L, the external load L1, and the neutral terminal N, and the current in the loop passes through the rectifying unit MB1, the circuit abnormality detector 3, the resistor R1, and then becomes a suitable output voltage through the AC-DC switching power supply 1 to supply power to the communication and control circuit 2; further, if the voltage of the AC-DC switching power supply 1 after primary transformation does not meet the requirement of the whole circuit, secondary or multiple voltage transformation can be performed by a voltage transformation circuit such as an LDO, a DC-DC, etc., until the output voltage meets the power supply requirement of the communication and control circuit 2; of course, the single live wire power supply circuit further includes other circuits such as a power supply circuit, a voltage stabilizing circuit, a filter circuit, and the like, and details thereof are not repeated herein.
It should be noted that the communication and control circuit 2 includes a control circuit (for example, a relay, etc.) for controlling the switching device S1 and a wireless communication circuit (for example, a radio frequency communication module, a WIFI communication module, a bluetooth communication module, etc.); the wireless communication circuit may adopt zigbee, bluetooth, wifi, or the matter and other standard wireless communication protocols, or may also be a self-defined radio frequency communication protocol, as long as the requirement of low power consumption is met, and this embodiment is not particularly limited. The rectifying unit MB1 may be implemented as a rectifying bridge (as in fig. 1-1) to form a full-wave rectifying circuit; in other embodiments, the rectifying unit MB1 may also be implemented as a rectifying diode, thereby forming a half-wave rectifying circuit; of course, the above two embodiments are only for example and are not intended to limit the present invention, and the rectifying unit MB1 may also be implemented as other electronic components with rectifying function or as a circuit with rectifying function combining a plurality of electronic components, without departing from the scope of the present invention. In addition, the load L1 includes, but is not limited to, a light fixture, an electrical appliance; the switching device S1 controls the operating state of the external load L1 including, but not limited to, switching the operating state of the external load L1 by controlling the on and off of the operating current supplied to the external load L1.
In the above technical solution, the circuit abnormality detector 3 connected in series to the resistor R1 is arranged to detect an abnormal condition of the circuit, and when the first state parameter is detected to be in a first designated interval starting from a first designated threshold, the circuit enters a high impedance state to protect the resistor R1, so as to achieve the purpose of protecting the whole circuit when the abnormal condition occurs in the circuit.
In the present embodiment, the circuit abnormality detector 3 is comprised of a positive temperature coefficient recoverable fuse R2; the ptc recoverable fuse R2 is connected in series with the resistor R1 and is electrically connected to the rectifying unit MB1, either directly or indirectly. The PTC recoverable fuse R2 is a recoverable circuit component, so that the normal operation of the circuit can be recovered after the abnormal condition of the circuit is relieved.
Therefore, in this embodiment, the circuit abnormality detector is further configured to, when detecting that the first state parameter is in a non-first specified range, release the high impedance state to recover the normal operation of the single live power protection circuit. In this embodiment, the circuit abnormality detector 3 is provided as a positive temperature coefficient recoverable fuse R2, and when an abnormality occurs in a circuit, the positive temperature coefficient recoverable fuse R2 enters a high impedance state and the resistance value of the resistor R1 increases to prevent the temperature of the resistor R1 from rising to damage the circuit or the device; when the abnormal condition of the circuit is relieved, namely the first state parameter is in a non-first specified range, the high impedance state is relieved to restore the normal operation of the circuit, so that the protection circuit has a self-restoring function and is more convenient to use.
In this embodiment, a clamping device (e.g., a clamping diode as shown in fig. 1-2) for limiting the voltage across the resistor R1 is not connected in parallel across the resistor R1. In one example, as shown in fig. 1-2, if the two ends of the resistor R1 are connected in parallel with a clamping diode D1; d1 may enter a clamped state when the voltage across the resistor R1 is greater than a certain threshold to protect the resistor R1, but the clamping action of the clamping diode D1 causes the voltage across the resistor R1 to clamp to a fixed value; assuming that the external load L1 is implemented as an LED lamp, since the LED lamp is driven by a constant power, it is characterized in that: the voltage at two ends of the LED lamp is high, the current is small, the voltage at two ends of the LED lamp is low, the current is large, the clamping effect of D1 can limit the rise of the voltage at two ends of R1, the voltage at two ends of the LED lamp is larger than that without clamping, the current is further reduced, the positive temperature coefficient restorable fuse R2 acts by the current, if the change of the current is small, the action of the positive temperature coefficient restorable fuse R2 is not facilitated, therefore, under the condition that the external load L1 is implemented as the LED lamp, the clamping effect of D1 affects the action of the positive temperature coefficient restorable fuse R2, and further affects the protection effect of the positive temperature coefficient restorable fuse R2 on a circuit; therefore, when the external load L1 is implemented as an LED lamp, in the case where the resistor R1 is connected in series with the ptc recoverable fuse R2, the two ends of the resistor R1 should no longer be connected in parallel with the clamping device 4 for limiting the voltage across the resistor R1.
In this embodiment, the ptc recoverable fuse R2 is electrically connected to the rear end of the rectifying unit MB1 after being connected in series with the resistor R1; as shown in fig. 1-1, one end of the ptc recoverable fuse R2 is electrically connected to the positive electrode of the rectifying unit as an input end, and the other end is electrically connected to the resistor R1 as an output end, for detecting the current flowing through the resistor R1. Of course, in other embodiments, one end of the ptc recoverable fuse R2 may also be electrically connected to the negative electrode of the rectifying unit as an input end, and the other end may be electrically connected to the resistor R1 as an output end. Regardless of the connection method, in the present embodiment, the ptc recoverable fuse R2 is used to detect the current in the resistor R1, and then determine to enter or release the high impedance state according to the magnitude of the current.
Further, in the present embodiment, the first state parameter includes the current of the resistor R1, the first specified threshold includes a specified current threshold, and the first specified interval includes a specified current interval; when the first state parameter is detected to be in a first specified interval taking a first specified threshold value as a starting point, entering a high impedance state; when the first state parameter is detected to be in a non-first specified range, the high impedance state is released; the method specifically comprises the following steps:
the ptc recoverable fuse R2 enters a high impedance state when it detects (or senses) that the current to the resistor R1 is within a specified current interval starting at the specified current threshold to limit the current to the resistor R1 within the specified current threshold range.
The ptc recoverable fuse R2 releases the high impedance state when it detects that the current of the resistor R1 is in a non-specified current interval.
It should be noted that the PTC recoverable fuse R2 is a device made of PTC material, which has an operating current, and is configured to be in a high-resistance state when the current of the resistor R1 is greater than the operating current, so as to equivalently disconnect a failed working circuit in an abnormal condition, thereby avoiding that the current of the resistor R1 is further increased in the abnormal condition, or a product is burned out at a high temperature due to continuous passing of abnormal current. The action current is a fixed parameter of R2, and the action current is different according to different types of the PTC resettable fuse R2.
It should be noted that the operating principle of the ptc recoverable fuse R2 is that it exhibits different resistance values depending on the temperature change, and its RT (resistance temperature) curve is shown in fig. 1-3, when it is in normal operation, because the operating current in the circuit is small, the heat generated by the current flowing in R2 is not enough to make the temperature of R2 reach the curie temperature, and the resistance value of R2 always exhibits the low resistance Rp set when it leaves the factory, and generally does not exceed Rmin; when the circuit is in an abnormal condition (for example, an open circuit), the working current in the circuit is abnormally increased, so that the temperature of the R2 is also rapidly increased, when the working current in the circuit is greater than or equal to the action current of the R2, the temperature of the positive temperature coefficient recoverable fuse R2 is increased to the curie temperature Tm (for example, 130 ℃), the resistance value of the positive temperature coefficient recoverable fuse R2 jumps to Rmax in a step-like manner, and meanwhile, the working current of the loop is rapidly reduced, so that the loop is equivalently an open loop, namely, the positive temperature coefficient recoverable fuse R2 enters a high impedance state; the specified current threshold can be understood as the action current; correspondingly, the specified current interval can be understood as a current interval which is greater than or equal to the action current; further, the non-specified current interval is a current interval smaller than the action current; it is further known that the specified current interval and the non-specified current interval jointly form a continuous current interval.
It is noted that the ptc recoverable fuse R2 also has a balanced condition; the method specifically comprises the following steps: as shown in fig. 1-3, when the resistance value of R2 increases to Rmax, the current in the resistor R1 will be pulled low, the temperature of the ptc recoverable fuse R2 itself decreases due to the drop-back of the current in the loop, its resistance value will decrease with the decrease in temperature, and again cause the rise-back of the current in the loop; this is cycled so that the circuit eventually reaches an equilibrium state (e.g., Tc in fig. 1-3). In this embodiment, when the ptc recoverable fuse R2 is in a balanced state, the current of the resistor R1 is less than or equal to 10 mA. In this equilibrium state, the resistor R1 is protected from being damaged by the temperature rising too high, and after the abnormal condition is resolved, the high impedance state can be rapidly resolved to restore the normal operation of the circuit.
Therefore, when the first state parameter is detected to be in a first specified interval taking a first specified threshold value as a starting point, entering a high impedance state; it can be understood that the high impedance state is entered immediately or after a preset time; the high impedance state may further be understood as a state where the ptc recoverable fuse R2 is in a high impedance equilibrium state; when the entering of the high impedance state is understood to be entering of the high impedance state after a preset time; the predetermined time may be determined according to the interval between the Rmin point and the Rmax point in fig. 3. For example, T2-T1, where T1 corresponds to the time corresponding to Rmin points and T2 corresponds to the time corresponding to Rmax points. In the above technical solution, the ptc recoverable fuse R2 does not immediately enter the high impedance state after reaching the specified current threshold, but enters the high impedance state after a preset time, so as to give a certain time buffer to the circuit system, thereby preventing the circuit state from being suddenly switched to damage electrical components in the circuit.
In the present embodiment, the action current is set to 5mA to 100 mA; further, it may be set to 20 mA. The specific setting basis is as follows: when the external load L1 is implemented as a lamp, the selection of the ptc recoverable fuse R2 is very important due to the power limitation of the lamp, and the larger the power of the lamp is, the larger the current flowing through the resistor R1 after the circuit failure due to an abnormal condition is, and the easier the ptc recoverable fuse R2 is to operate, so that the current under the lamp load with the minimum power needs to be considered to select the device; in one assumption, if the power of the external load L1 with the minimum power is 3W, under the condition of 220V power supply, the current of the lamp load is about 13mA, the voltage at two ends of the lamp is reduced due to the existence of the resistor R1 in the loop, and the current of the lamp is increased (the power is constant, and the current is increased when the voltage is reduced), so the operating current larger than 13mA can completely meet the design requirement, but in practical application, the relationship between the normal current requirement and the current to be protected is considered due to engineering deviation, such as deviation of the operating current of the ptc recoverable fuse R2, deviation of the lamp power, and the like, the ptc recoverable fuse R2 with the operating current of 5mA to 100mA is selected in a compromise way. In some application scenarios, for example, in ultra-low power applications, the requirement of the back-end circuit in a normal state can be satisfied with a current of only several hundred microamperes, and in this case, the action current of 5mA can be selected to ensure that the ptc recoverable fuse R2 can act in an abnormal situation. In some application scenarios, for example, a protocol with slightly large power consumption, such as wifi connection, requires an operating current of several milliamperes, and thus the operating current in such a case needs to be set to be larger, for example, to 20mA, 30mA, or 50 mA. Therefore, in this embodiment, the operating current of the ptc recoverable fuse R2 is set to be in the range of 5mA to 100mA to make the ptc recoverable fuse R2 suitable for most usage scenarios.
As shown in fig. 2-1, it is a schematic circuit diagram of an embodiment 2 of the single live line protection circuit according to the present invention; unlike the above embodiment, in this embodiment, the ptc recoverable fuse R2 and the resistor R1 are connected in series and then disposed at the front end of the rectifying unit MB 1; as shown in fig. 2-1, the ptc recoverable fuse R2 is electrically connected between the live wire end of the single live wire protection circuit and the rectifying unit MB1 after being connected in series with the resistor R1, and is configured to detect a current of the resistor; certainly, in other embodiments, the ptc recoverable fuse R2 and the resistor R1 may also be electrically connected between the zero line end of the single live wire protection circuit and the rectifying unit after being connected in series, as long as the same technical effect can be achieved, which is not limited in this embodiment.
Other connection relationships and parameter designs under the present embodiment refer to the discussion of embodiment 1 above, and are not described herein in a repeated manner.
In addition, in consideration of the characteristics of the alternating current, when the ptc recoverable fuse R2 is connected in series with the resistor R1 and then disposed at the front end of the rectifying unit MB1, the non-specified current interval is a current interval with an absolute value smaller than the first preset current value. It can be seen that, in the present embodiment, the designated current interval and the non-designated current interval together form a continuous current interval, that is, the current value of the resistor R1 is in either the designated current interval or the non-designated current interval.
In this embodiment, the ptc recoverable fuse R2 and the resistor R1 are connected in series and then disposed at the front end of the rectifying unit MB 1. Compared with the arrangement mode of the embodiment, the arrangement mode has larger protection range; a failure fault like a short circuit caused by, for example, the rectifying unit MB1 may also be within the protection range of the ptc recoverable fuse R2 and the resistor R1. In this case, if clamp protection is required, a clamp device 4 composed of two clamp diodes (D1 and D2) connected in series with the same polarity as shown in fig. 2-2 is required, so that the whole ac cycle has a clamping effect, the clamp diodes may be voltage regulator tubes or anti-surge schottky diodes, and play roles of clamping and surge suppression, but as discussed in the above embodiment regarding the clamp diodes, this clamping effect may cause a problem of immobility of the ptc recoverable fuse R2 under certain circumstances, and therefore when the ptc recoverable fuse R2 and the resistor R1 are connected in series and then can be restored to the front end of the rectifier unit MB1, the clamp device 4 should not be connected in parallel at both ends of the resistor R1.
As shown in fig. 3, which is a schematic circuit diagram of an embodiment 3 of the single live wire protection circuit provided in the present invention; in this embodiment, the external loads are multiple (L1, L2, L3), and in this embodiment, the circuit structure shown in fig. 3 is adopted to ensure that any one of the loads is connected, and the communication and control circuit 2 at the rear end can normally take power;
further, in this embodiment, each load (L1, L2, or L3) needs to be added with a resistor, such as R1, R3, R4 of fig. 3; the suppression resistance corresponding to the external load L1 is R1, the suppression resistance corresponding to the external load L2 is R3, and the suppression resistance corresponding to the external load L3 is R4; the PTC recoverable fuse R2 is arranged at the common end of the whole circuit, so that the PTC recoverable fuse R2 can play a role in safety when any load fails.
Further, as shown in fig. 3, the circuit realizes the connection of any load through two rectifying units (MB1 and MB2), and the communication and control circuit 2 can take electricity; one path of external load (L1) is directly or indirectly electrically connected to two ends of the ac input of the rectifying unit MB1, the other two paths of external loads (L2 and L3) are respectively directly or indirectly electrically connected to one end of the ac input of the other rectifying unit MB2, the negative electrode of the rectifying bridge MB1 is electrically connected to the negative electrode of the MB2, and the positive electrode of the rectifying bridge MB1 is electrically connected to the positive electrode of the MB 2. The functions of S2 and S3 of the circuit are the same as S1, and the circuit is set to be switched on or off under the control of the communication and control circuit 2 so as to control the working state of the corresponding external load; as shown in fig. 3, in the present embodiment, MB1 and MB2 are each provided as a rectifier bridge; other functions and designs are discussed in the same way as the corresponding embodiments of fig. 1-1 to 1-3 and will not be described again here.
The circuit abnormality detectors 3 of the above embodiments 1 to 3 are all positive temperature coefficient recoverable fuses R2, and are characterized in that after the failure is resolved, normal operation can still be recovered without permanent damage. So as to realize the functions of self-protection and self-recovery of the circuit.
As shown in fig. 4-1, it is a circuit schematic diagram of an embodiment 4 of the single hot wire protection circuit according to the present invention; in this embodiment, the ptc recoverable fuse R2 in the above embodiment is replaced with a temperature fuse, and the maximum damage of the circuit failure fault is heat generation caused by long-term current, so that the guarantee effect of the temperature fuse is more direct, and the circuit is determined to be abnormal as long as the temperature is greater than a preset value regardless of the failure fault. Illustratively, the temperature fuse device is implemented as a temperature sensitive fuse and/or a semiconductor logic circuit with temperature sensing.
In this embodiment, the temperature fuse is electrically connected to the rear end of the rectifying unit MB1 after being connected in series with the resistor R1; as shown in fig. 4-1, one end of the temperature safety device is electrically connected to the anode of the rectifying unit MB1 as an input end, and the other end is electrically connected to the resistor R1 as an output end, for detecting the current flowing through the resistor R1. Of course, in other embodiments, one end of the temperature safety device may also be electrically connected to the cathode of the rectifying unit MB1 as an input end, and the other end is electrically connected to the resistor R1 as an output end. Regardless of the connection method, in this embodiment, the temperature safety device is used to detect the temperature of the resistor R1, and then blows at a certain temperature point, so that the whole circuit is broken to present a high impedance state with infinite resistance.
As discussed with respect to the clamping diode D1 of fig. 1-2, the heat generating device in this embodiment is primarily resistor R1, and thus in order to cooperate with the temperature fuse device to expose the problem as quickly as possible, there is still no need for an additional clamping device 4 similar to that of fig. 4-2.
In this embodiment, the first state parameter includes a temperature, the first specified threshold includes a specified temperature threshold, and the first specified interval includes a specified temperature interval; when the first state parameter is detected to be in a first specified interval taking a first specified threshold value as a starting point, entering a high impedance state; the method specifically comprises the following steps: and when the temperature of the resistor is detected to be in a specified temperature interval with a specified temperature threshold value as a starting point, the resistor is fused to disconnect the circuit, and then a high impedance state with infinite resistance is presented. It is noted that the specified temperature threshold is a preset value, and the specified temperature interval is a temperature interval greater than or equal to the specified temperature threshold.
In this embodiment, the temperature fuse blows when the temperature of the resistor R1 reaches a predetermined temperature threshold, so as to open the circuit, thereby protecting the resistor R1 and the entire circuit. The temperature safety device can not be recovered after being disconnected, can force workers to check the problem point of the circuit abnormal condition, and can visually expose the problem when the abnormal condition occurs, so that the problem can be solved as soon as possible, and potential safety hazards can be prevented from being left.
In the present embodiment, the operation temperature of the temperature safety device is designed to be 120 ℃ to 200 ℃, preferably 145 ℃ in consideration of the safe temperature that the circuit board, the equipment case, and the like can withstand, and the temperature at which the circuit normally operates. The temperature fuse device can select a fuse of a temperature fusing type, when the operating temperature is reached, the fuse is disconnected and cannot be recovered, the circuit cannot be recovered, the failure of the circuit after the failure is ensured, and unsafe factors which cannot be found after the failure are avoided. Other functions of the circuit are similar to those of the above embodiment, and those skilled in the art can refer to the discussion of the above embodiment (embodiment 1), and will not be repeated here.
In this embodiment, the temperature safety device and the resistor R1 need to be closely arranged, specifically, spaced apart by a distance less than a preset threshold distance, to ensure that the temperature safety device can accurately detect the temperature of the resistor R1, and prevent circuit failure due to slow detection. In one embodiment, a thermally conductive material is applied between the temperature fuse and the resistor R1 to allow heat from the resistor R1 to be efficiently transferred to the temperature fuse. In another embodiment, the temperature fuse and resistor R1 are packaged together for better placement and heat transfer.
As shown in fig. 5-1, which is a schematic circuit diagram of an embodiment 5 of the single hot wire protection circuit according to the present invention; unlike the above embodiment 4, in this embodiment, a temperature fuse device is provided at the front end of the rectifying unit MB 1; as shown in fig. 5-1, the temperature fuse device is connected in series with the resistor R1 and then disposed between the live line end of the single live line protection circuit and the rectifying unit, so as to detect the temperature of the resistor R1. Of course, in other embodiments, the temperature safety device and the resistor R1 may be electrically connected between the zero line end of the single live wire protection circuit and the rectifying unit MB1 after being connected in series, as long as the same technical effect can be achieved, which is not limited in this embodiment.
As discussed with respect to the clamping diode D1 of fig. 1-2, the heat generating device in this embodiment is primarily resistor R1, and thus in order to cooperate with the temperature fuse device to expose the problem as quickly as possible, there is still no need for an additional clamping device 4 similar to that of fig. 5-2.
Other circuit structures and functional principles of the present embodiment are similar to those of the above embodiments, and those skilled in the art can refer to the corresponding related discussion of embodiments 2 and 4, and will not be repeated here.
Fig. 6 is a schematic circuit diagram of a single live line protection circuit according to an embodiment 6 of the present invention; in this embodiment, the external loads are multiple (L1, L2, L3), and the circuit structure shown in fig. 6 is adopted to ensure that any one of the loads is connected, and the communication and control circuit 2 at the rear end can normally take power;
referring to fig. 3 (embodiment 3), the positive temperature coefficient recoverable fuse R2 is replaced with a temperature fuse device in this embodiment. In this embodiment, each load needs to add a resistor, such as R1, R3, R4 in fig. 6; the suppression resistance corresponding to the external load L1 is R1, the suppression resistance corresponding to the external load L2 is R3, and the suppression resistance corresponding to the external load L3 is R4; the temperature safety device is arranged at the common end of the whole loop, so that one temperature safety device can play a safety role when any one load fails.
Further, as shown in fig. 3, the circuit realizes the connection of any load through two rectifying units (MB1 and MB2), and the communication and control circuit 2 can take electricity; one path of external load (L1) is directly or indirectly electrically connected to two ends of the alternating current input of the rectifying unit MB1, the other two paths of external loads (L2 and L3) are respectively directly or indirectly electrically connected to one end of the alternating current input of the other rectifying unit MB2, the negative electrode of the rectifying bridge MB1 is electrically connected to the negative electrode of the MB2, and the positive electrode of the rectifying bridge MB1 is electrically connected to the positive electrode of the MB 2. The functions of S2 and S3 of the circuit are the same as S1, and the circuit is set to be switched on or off under the control of the communication and control circuit 2 so as to control the working state of the corresponding external load; as shown in fig. 6, in the present embodiment, MB1 and MB2 are each provided as a rectifier bridge; other functions and designs are discussed in the same way as in the corresponding embodiment of fig. 3 and will not be described again here.
In the above embodiment, the three resistors (R1, R3, R4) are all heat generating sources, and therefore the temperature safety device is disposed at a common position of the three resistors, so that the temperature safety device can detect the temperatures of the three resistors at the same time, and further when the temperature of the resistor corresponding to any one external load abnormally rises, the temperature safety device can be blown out to make the circuit enter a high impedance state with infinite resistance, so as to protect the corresponding resistor (R1, R3 or R4) and the whole circuit.
Fig. 7 is a schematic circuit diagram of a single live line protection circuit according to an embodiment 7 of the present invention; the difference between this embodiment and embodiment 6 is that only the power-taking function of one external load (L3) loop is retained, and the external loads (L1 or L2) of the other loops are not provided with power-taking loops. In the embodiment, the temperature fuse device and the resistor (R1, R3 or R4) are only required to be one, so that the use number of the devices is saved. Of course, the temperature fuse device shown in fig. 7 may be replaced by a ptc recoverable fuse R2, and the principle can be referred to the above-described embodiment and will not be described again here.
The utility model further provides a single live wire power-taking protection circuit, which is specifically shown in fig. 8 and is a circuit schematic diagram of an embodiment 8 of the single live wire power-taking protection circuit provided by the utility model; referring to fig. 8, the single hot wire protection circuit of the present embodiment at least includes a resistor R1; a clamping device 4 connected in parallel across the resistor R1 and adapted to detect a second state parameter of the resistor R1, and enter a clamping state to protect the resistor R1 when the second state parameter is detected to be in a second designated interval starting at a second designated threshold.
In the above technical solution, the clamp device 4 connected in parallel to the resistor R1 is arranged to detect an abnormal condition of the circuit, and when it is detected that the second state parameter associated with the resistor R1 is in the second designated interval starting from the second designated threshold, the clamp device enters the clamp state to protect the resistor R1, thereby achieving the purpose of protecting the whole circuit.
In this embodiment, the clamping device 4 is further configured to, when detecting that the second state parameter is in a non-second specified range, release the clamping state, so as to recover the normal operation of the single live wire protection circuit, thereby implementing the self-detection and self-recovery function of the single live wire protection circuit.
In this embodiment, a circuit abnormality detector (a positive temperature coefficient recoverable fuse R2 or a temperature fuse device, etc.) for limiting the current of the resistor R1 does not need to be connected in series at either end of the resistor R1, for similar reasons as discussed above in connection with embodiment 1, and will not be described again here.
In this embodiment, the clamping device includes a first clamping diode D3; as shown in fig. 8, the first clamping diode D3 is electrically connected to the rear end of a rectifying unit MB1 after being connected in parallel with the resistor R1, and the first clamping diode D3 is connected to the positive electrode of the rectifying unit MB1 after being connected in parallel with the resistor R1, and is used for detecting the current flowing through the resistor R1. Of course, in other embodiments, the first clamping diode D3 may be electrically connected to the negative electrode of the rectifying unit MB1 after being connected in parallel with the resistor R1.
Of course, in other embodiments, the first clamping diode D3 may be connected in parallel with the resistor R1 and then disposed at the front end of the rectifying unit MB 1; namely, the voltage at two ends of the resistor is detected between the live wire end of the single live wire power-taking protection circuit and the rectifying unit or between the zero line end of the single live wire power-taking protection circuit and the rectifying unit.
In this embodiment, the first clamping diode D3 is used to detect the voltage across the resistor R1, and to enter or release the clamping state according to the magnitude of the voltage. The first clamping diode D3 has a clamping effect on the voltage across the resistor R1, and when the voltage across the resistor R1 is greater than a certain voltage value, the first clamping diode D3 clamps to limit the voltage across the resistor R1 from increasing further, so as to protect the resistor R1.
Fig. 9 is a schematic circuit diagram of a single live line protection circuit according to an embodiment 9 of the present invention; in this embodiment, the clamping device 4 includes a second clamping diode D4 and a third clamping diode D5; one end of the second clamping diode D4 and one end of the third clamping diode D5 with the same polarity are electrically connected, and the two ends which are not connected correspondingly are connected in parallel to the two ends of the resistor R1; the second clamping diode D4 and the third clamping diode D5 are electrically connected to the front end of a rectifying unit MB1 after being connected in parallel with the resistor R1, that is, as shown in fig. 9, the second clamping diode D4 and the third clamping diode D5 are electrically connected to the front end of the single live line protection circuit after being connected in parallel with the resistor R1, and then are electrically connected between the live line end of the single live line protection circuit and the rectifying unit MB 1; in another embodiment, the second clamping diode D4 and the third clamping diode D5 are electrically connected between the live wire end of the single live wire protection circuit and the rectifying unit MB1 after being connected in parallel with the resistor R1, and are used for detecting the voltage across the resistor R1; and the rectifying unit MB1 is used for rectifying and outputting the current input by the power input stage of the single live wire power-taking protection circuit.
In another embodiment, the second clamping diode D4 and the third clamping diode D5 are electrically connected to the rear end of a rectifying unit MB1 after being connected in parallel with the resistor R1, that is, the second clamping diode D4 and the third clamping diode D5 are electrically connected to the positive pole or the negative pole of the rectifying unit MB1 after being connected in parallel with the resistor R1, and are used for detecting the voltage across the resistor R1.
When the clamping device 4 is disposed at the front end of the rectifying unit MB 1; since the clamp device 4 has an ac clamp function, it is necessary to implement the clamp device 4 as a clamp circuit in which the same poles of two clamp diodes (D4 and D5) are connected, and the other poles of the two clamp diodes (D4 and D5) are connected to both ends of a resistor R1 in a loop.
Further, in this embodiment, the two clamping diodes (D4 or D5) may be a voltage regulator tube, and may also be a surge suppression diode; preferably, the protection circuit is implemented as a surge suppression diode, and the power of the surge suppression diode is higher, so that the protection circuit is more suitable for the protection application.
In this embodiment, the second state parameter includes a voltage, the second specified threshold includes a specified voltage threshold, and the second specified interval includes a specified voltage interval; when the second state parameter is detected to be in a second specified interval taking a second specified threshold value as a starting point, entering a clamping state; said removing said clamped state upon detecting said second state parameter being within a non-second specified range; the method specifically comprises the following steps:
entering a clamping state to limit the voltage across the resistor R1 within a specified voltage threshold range upon detecting that the voltage across the resistor R1 is within the specified voltage interval starting at the specified voltage threshold;
when the voltage across the resistor R1 is detected to be in a non-specified voltage interval, the clamping state is released to restore the normal operation of the circuit.
It should be noted that: the specified voltage interval is a voltage interval which is greater than or equal to the specified voltage threshold, and the non-specified voltage interval is an interval which is less than the specified voltage threshold; or the specified voltage interval is a voltage interval greater than the specified voltage threshold, and the non-specified voltage interval is an interval less than or equal to the specified voltage threshold; when the clamping device 4 is disposed at the front end of the rectifying unit MB1, the non-specific voltage interval is a voltage interval whose absolute value is smaller than the specific voltage threshold (the specific voltage threshold is positive) in consideration of the characteristics of the alternating current. It can be seen that, in the present embodiment, the specified voltage interval and the non-specified voltage interval together form a continuous voltage interval, that is, the voltage value across the resistor R1 is either in the specified voltage interval or in the non-specified voltage interval.
The utility model has the beneficial effects that: the technical scheme provided by the utility model detects the abnormal condition of the circuit by arranging a circuit abnormality detector connected in series with a resistor or a clamping device connected in parallel with the resistor; when the circuit abnormity detector connected in series with the resistor is used, the current or the temperature of the resistor is detected, and when the current or the temperature of the resistor is abnormal, the circuit abnormity detector enters a high-impedance state to rapidly pull down the current of a loop, so that the aim of protecting the resistor and the whole circuit is fulfilled; when a clamping device connected in parallel is used, the voltage across the resistor is detected, and when the voltage of the resistor is abnormal, the clamping device enters a clamping state to limit the voltage across the resistor within a threshold range so as to indirectly prevent the increase of the loop current and protect the resistor and the circuit. In addition, according to the technical scheme provided by the application, only one of the circuit abnormality detector and the clamping device needs to be selected as a protection measure for taking electricity by single fire, and a better protection effect can be achieved under the condition of lower cost.
In addition, the utility model further provides an electronic device which comprises at least part of the single live wire protection circuit in the embodiment. The electronic device may be an intelligent switch; the intelligent switch is powered by a single live wire power supply mode, and any one or more single live wire power supply protection circuits in the embodiments 1 to 9 are arranged in a circuit of the intelligent switch. The electronic equipment is provided with the single live wire power-taking protection circuit to process faults caused by circuit abnormality in the power-taking process, and the condition that the equipment is burnt out due to heating caused by abnormal current flowing through the resistor connected in series in the single live wire power-taking circuit for a long time is prevented.
In the description herein, reference to the terms "an embodiment," "an example," "a specific implementation," "an example," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the utility model has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (29)

1. A single live wire power-taking protection circuit is characterized by comprising:
the resistor is electrically connected in the single live wire power-taking protection circuit;
a circuit abnormality detector connected in series to the resistor and adapted to detect a first state parameter of the resistor, and enter a high impedance state upon detecting that the first state parameter is in a first specified interval starting at a first specified threshold.
2. A single hot wire protection circuit according to claim 1, wherein the circuit abnormality detector is further arranged to release the high impedance state upon detecting that the first state parameter is in a non-first specified range.
3. The single hot wire protection circuit according to claim 1, wherein a clamp device for limiting a voltage across the resistor is not connected in parallel across the resistor.
4. The single fire power protection circuit according to claim 2, wherein the circuit abnormality detector comprises a positive temperature coefficient recoverable fuse; the positive temperature coefficient restorable fuse is connected in series with the resistor and is directly or indirectly electrically connected with a rectifying unit; and the rectifying unit is used for rectifying and outputting the input current of the single live wire power-taking protection circuit.
5. The single live wire protection circuit according to claim 4, wherein the PTC recoverable fuse is electrically connected to the rear end of the rectifying unit after being connected in series with the resistor; namely, one end of the PTC recoverable fuse is used as an input end to be directly or indirectly electrically connected to the anode or the cathode of the rectifying unit, and the other end of the PTC recoverable fuse is used as an output end to be electrically connected to the resistor and used for detecting the current of the resistor.
6. The single live wire power-taking protection circuit according to claim 4, wherein the positive temperature coefficient recoverable fuse is electrically connected to the front end of the rectifying unit after being connected in series with the resistor, namely between a live wire end of the single live wire power-taking protection circuit and the rectifying unit, or between a zero wire end of the single live wire power-taking protection circuit and the rectifying unit, and is used for detecting the current of the resistor.
7. The single hot wire protection circuit according to claim 5 or 6, wherein the first state parameter comprises a current of the resistor, the first specified threshold comprises a specified current threshold, and the first specified interval comprises a specified current interval; the positive temperature coefficient recoverable fuse is arranged to:
and when the current of the resistor is detected to be in a specified current interval with a specified current threshold as a starting point, entering a high impedance state to limit the current of the resistor within the specified current threshold range.
8. The single hot wire protection circuit according to claim 5 or 6, wherein the first state parameter comprises a current of the resistor, the first specified threshold comprises a specified current threshold, and the non-first specified interval comprises a non-specified current interval; the PTC recoverable fuse is configured to:
and when the current of the resistor is detected to be in a non-specified current interval, the high impedance state is released.
9. The single live wire electricity-taking protection circuit according to claim 4, wherein multiple paths of loads are arranged in parallel, and correspondingly, each path of load is connected to a rectifying unit; the positive temperature coefficient recoverable fuse is connected to a loop shared by all the rectifying units.
10. A single fire power protection circuit according to any one of claims 4 to 6 or 9 wherein the ptc recoverable fuse is set to operate at a current in the range 5mA to 100 mA.
11. A single fire power protection circuit according to any one of claims 4 to 6 or 9 wherein the ptc recoverable fuse is set to 20 mA.
12. A single fire power protection circuit according to any one of claims 4 to 6 or 9 wherein the ptc recoverable fuse has a resistor current of less than or equal to 10mA at equilibrium.
13. The single hot wire protection circuit according to claim 1, wherein the circuit abnormality detector comprises a temperature fuse device; the temperature fuse device is connected in series with the resistor and is directly or indirectly electrically connected with a rectifying unit; and the rectifying unit is used for rectifying and outputting the input current of the single live wire power-taking protection circuit.
14. The single live wire protection circuit according to claim 13, wherein the temperature safety device is electrically connected to the rear end of the rectifying unit after being connected in series with the resistor; namely, the input end of the temperature safety device is directly or indirectly electrically connected to the anode or the cathode of the rectifying unit, and the output end of the temperature safety device is electrically connected to the resistor for detecting the temperature of the resistor.
15. The single live wire electricity-taking protection circuit according to claim 13, wherein the temperature safety device is electrically connected to the front end of the rectifying unit after being connected in series with the resistor, that is, between a live wire end of the single live wire electricity-taking protection circuit and the rectifying unit, or between a null wire end of the single live wire electricity-taking protection circuit and the rectifying unit, and is configured to detect the temperature of the resistor.
16. The single hot wire taking protection circuit according to claim 14 or 15, wherein the first state parameter comprises temperature, the first specified threshold comprises a specified temperature threshold, and the first specified interval comprises a specified temperature interval; the temperature fuse device is configured to:
is blown to assume a high impedance state of infinite resistance when the temperature of the resistor is detected to be in a specified temperature interval starting at a specified temperature threshold.
17. A circuit for protecting against electric shock as claimed in any one of claims 13 to 15, wherein the operating temperature of the temperature fuse device is set to a range of 120 ℃ to 200 ℃.
18. A single live wire protection circuit as claimed in any one of claims 13 to 15, wherein the temperature safety device and the resistor are both disposed on a PCB, the distance between which is less than a threshold distance; and a heat conducting material is coated between the temperature fuse element and the resistor.
19. A single live wire protection circuit according to any one of claims 13 to 15 wherein the temperature safety device is integrally packaged with the resistor such that the temperature safety device can accurately sense the temperature of the resistor.
20. A single live wire power-taking protection circuit is characterized by comprising:
a resistor; and
a clamping device connected in parallel across the resistor and configured to detect a second state parameter of the resistor, and enter a clamping state to protect the resistor when the second state parameter is detected to be within a second specified interval starting at a second specified threshold.
21. The single hot trip protection circuit as claimed in claim 20, wherein the clamping device is further arranged to release the clamped state upon detection of the second state parameter being in a non-second specified range.
22. The single hot wire electrical protection circuit of claim 20, wherein no circuit abnormality detector for limiting the resistor current is connected in series at either end of the resistor.
23. The single hot wire electrical protection circuit of claim 21, wherein said clamping device comprises a first clamping diode; the first clamping diode and the resistor are connected in parallel and then electrically connected to the rear end of a rectifying unit, namely the first clamping diode and the resistor are connected in parallel and then electrically connected to the anode or the cathode of the rectifying unit and used for detecting the voltage at two ends of the resistor; and the rectifying unit is used for rectifying and outputting the current input by the power input stage of the single live wire power-taking protection circuit.
24. The single hot wire electrical protection circuit of claim 21, wherein said clamping device comprises a first clamping diode; the first clamping diode is electrically connected to the front end of a rectifying unit after being connected in parallel with the resistor, namely, the first clamping diode is arranged between the live wire end of the single live wire power-taking protection circuit and the rectifying unit or between the zero line end of the single live wire power-taking protection circuit and the rectifying unit and used for detecting the voltage at the two ends of the resistor; and the rectifying unit is used for rectifying and outputting the current input by the power input stage of the single live wire power-taking protection circuit.
25. The single hot trip protection circuit as claimed in claim 21, wherein said clamping device comprises a second clamping diode and a third clamping diode; the ends of the second clamping diode and the third clamping diode with the same polarity are electrically connected, and the two ends which are not connected correspondingly are connected in parallel with the two ends of the resistor; the second clamping diode and the third clamping diode are electrically connected to the rear end of a rectifying unit after being connected in parallel with the resistor, namely the second clamping diode and the third clamping diode are electrically connected to the anode or the cathode of the rectifying unit after being connected in parallel with the resistor and are used for detecting the voltage at two ends of the resistor; and the rectifying unit is used for rectifying and outputting the current input by the power input stage of the single live wire power-taking protection circuit.
26. The single hot line taking protection circuit of claim 21, wherein the clamping device comprises a second clamping diode and a third clamping diode; the second clamping diode and the third clamping diode are electrically connected to the front end of a rectifying unit after being connected in parallel with the resistor, namely between the live wire end of the single live wire power-taking protection circuit and the rectifying unit, or between the live wire end of the single live wire power-taking protection circuit and the rectifying unit, and are used for detecting the voltage at two ends of the resistor; and the rectifying unit is used for rectifying and outputting the current input by the power input stage of the single live wire power-taking protection circuit.
27. The single live wire protection circuit according to any one of claims 23 to 26, wherein the second state parameter comprises a voltage, the second specified threshold comprises a specified voltage threshold, and the second specified interval comprises a specified voltage interval; the clamping device is further configured to:
and when the voltage across the resistor is detected to be in a specified voltage interval with a specified voltage threshold as a starting point, entering a clamping state to limit the voltage across the resistor within the specified voltage threshold range.
28. The single live wire protection circuit according to any one of claims 23 to 26, wherein the second state parameter comprises a voltage, the second specified threshold comprises a specified voltage threshold, and the non-second specified interval comprises a non-specified voltage interval; the clamping device is further configured to; the method specifically comprises the following steps:
and when the voltage at the two ends of the resistor is detected to be in a non-specified voltage interval, the clamping state is released.
29. An electronic device comprising the single hot-line protection circuit of any one of claims 1-28.
CN202123269974.4U 2021-12-23 2021-12-23 Single-fire electricity-taking protection circuit and equipment Active CN216929581U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202123269974.4U CN216929581U (en) 2021-12-23 2021-12-23 Single-fire electricity-taking protection circuit and equipment

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202123269974.4U CN216929581U (en) 2021-12-23 2021-12-23 Single-fire electricity-taking protection circuit and equipment

Publications (1)

Publication Number Publication Date
CN216929581U true CN216929581U (en) 2022-07-08

Family

ID=82255497

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202123269974.4U Active CN216929581U (en) 2021-12-23 2021-12-23 Single-fire electricity-taking protection circuit and equipment

Country Status (1)

Country Link
CN (1) CN216929581U (en)

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